Lie detector has been used as party games, but in these instances the resulting decision if the answer is the truth or not depends to some extend on the person answering the question. In U.S. Pat. No. 3,841,316, a circuit is attached to the person answering the question which measures an apparent decrease in skin resistance of a human being in response to stress. The "lie Detector" of this patent may be used and sold as part of a toy "lie detector". However, the decision of whether the person is lying is based upon a galvanic reaction.
In U.S. Pat. No. 3,648,686, an audio signal is emitted in response to the galvanic skin response of the person being questioned.
Both of the above lie detectors depend upon an electrical connection to the person being questioned.
The use of radio signals is disclosed in U.S. Pat. No. 4,961,575. Radio signal senders and receivers are used in an enhanced hide-and-seek game.